A Quick Question About Speed Reducer Pulley Sizes

[OLDNSLOW]

I searched and did not find the answer to my question, and I can figure that the answer will very depending on weather it is store bought or home made, but would like to know what the common sizes of the speed reducer sets run.

Thanks to all who answer.

O n S

Ron

[Wishful]

If you are asking about what size the pulleys are I would say 9" and 3". There are a lot of variations. I am building one that has a 10 pulley and a smaller one that is a triple pulley that is 1.5,2.5 & 3 I believe.

[OLDNSLOW]

where are you going to put the 10 inch pulley?

[Uwe]

It's less about actual size than ratios between pulleys. A 2"/4"inch speed reducer pulley combo will have the same 2:1 speed-reducing effect as a 3"/6" combo. One popular commercial version actually has a three-in-one pulley : 3"/6"/9":

So depending on which two pulleys you put your belts on, you get a 1.5:1 (9":6"), 2:1 (6":3"), or 3:1 (9":3") ratio of speed reduction and torque increase.

Unless you're really into into wandering the aisles of your local hardware store and hours of tinkering, I highly recommend a commercial version. They're much easier to install and not much more expensive than home-made versions in my experience.

$130-$150 seems like a lot for two pieces of painted cast iron and a bearing, but I've yet to find a considerably better or cheaper alternative.

The only really cheaper way to reduce speed and increase torque is to change just the pulley on your motor to a smaller one. My Enduro motors come with 5" pulleys. Installing a 2" pulley is only $5 or so, but provides a very cheap 2.5:1 ratio improvement for speed reduction and torque increase.

If you want to go REALLY slow and REALLY high-torque, you do both, swap the motor pulley out for a smaller one AND install a speed reducer pulley BETWEEN the motor and machine.

Changing out the hand wheel on the machine is usually not a practical option.

Edited January 3, 2016 by Uwe

[dikman]

Uwe is right, it's a lot of messing around building pulley reducers - pulleys, suitable shaft, bearings of some sort, mounting for the bearings, a method of making the support adjustable. Those commercial ones might seem a bit on the expensive side, but they're neat, compact and relatively simple to fit.

As to size, if it's home-built it could be anything, depending on a) what the builder has lying around or what he can buy that's suitable. One of mine uses the typical 4"/1 3/4" pulleys that are commonly available on ebay (3/4" shaft). Another uses an 8" that I had lying around coupled with another 1 3/4". As for changing the handwheel, it's not that difficult, although it will obviously depend on the machine - my Singer 211G166 is a problem (which I'm working on). I'm a great believer in the handwheel option, although it may mean widening the belt slot on the table.

[OLDNSLOW]

Thanks for all the info.

[dikman]

Sorry about the smiley in my post, it's not supposed to be there! Apparently if I use a bracket and lower case b it inserts the smiley instead.

[Wishful]

I am making a variation of this, they go for over 200 so I thought I would give it a go. The 10" was the smallest big pulley they had at the hardware store so I am going with it. I already have a few smaller Pullies. The advantage to this type is that the machine will still tilt back and it bolts into the existing holes. Hopefully it will work....

http://i.ebayimg.com/00/s/NDgwWDY0MA==/z/X6UAAOxy7RBRYjjI/$T2eC16h,!yEE9s5jHPtcBRYjjIFHr!~~60_35.JPG

Some tips found here: http://makezine.com/2014/01/30/bandsaw-speed-changer-reducer/

Edited January 4, 2016 by Wishful

[TinkerTailor]

I am making a variation of this, they go for over 200 so I thought I would give it a go. The 10" was the smallest big pulley they had at the hardware store so I am going with it. I already have a few smaller Pullies. The advantage to this type is that the machine will still tilt back and it bolts into the existing holes. Hopefully it will work....

http://i.ebayimg.com/00/s/NDgwWDY0MA==/z/X6UAAOxy7RBRYjjI/$T2eC16h,!yEE9s5jHPtcBRYjjIFHr!~~60_35.JPG

Some tips found here: http://makezine.com/2014/01/30/bandsaw-speed-changer-reducer/

That first one you linked is a Cowboy and should be available from cowboy dealers btw.

Also, try heater/ac supply places. Older style of ventilation fans have belt drive pulleys on them. I also know heater guys would change belts to adjust air speed Also try farm and implement supply places. Farm stuff has belts everywhere. So do lawn mowers. I personally would hit the hardware store as the last resort for this part.

[OLDNSLOW]

well as it turns out I found a guy over the weekend that had a whole stack of pulleys all brand new with the bearings and shafts for sale for 25.00 so now I just need to put it all together.